I just got my huge box of header bending mistakes from Stahl headers today and am ready to start throwing my own set together. Has anyone built their own 3800 headers? If so, what should I look out for as potential problems and what were your design ideas? thanks

Look into the merge collectors to make your life easy and the stars to help the flow through the collector. They offer them at that place you went to also. I got mine through this place - http://www.coneeng.com/collectors.html

You would want several variety of sizes to make up the exhaust system. They would vary from 1.5" OD - 2" OD primaries into a 3 to 1 collector. Then a certain size after for the Y section. Followed by the 2 to 1 collector and the rest is up to you if you want a cat and muffler.

For my 3.4L OHV, I will start with a 1 5/8" OD into a 3 to 1 collector ( 1 5/8" the three side and 2" the one side ). 2" OD pipe for the Y section into the 2 to 1 collector ( 2" the two side and 2.5" the one side ). 2.5" the rest back through the cat and muffler...

As far as what sizes to pick from????? depends on your block. There are a lot of opinions on this site too for that. I figured the middle of the row.

Thanks for the info but i already ordered formed collectors and planned on fabbing bullets myself. For my 3.8 I'm using 1 5/8" primaries, 2 1/2" Y-pipe, and 3" from there back.

quote Originally posted by MJ: I just got my huge box of header bending mistakes from Stahl headers today and am ready to start throwing my own set together. Has anyone built their own 3800 headers? If so, what should I look out for as potential problems and what were your design ideas? thanks

The problem is you could have 60-80 hours into them and only be half done... its just not logistically easy, and with headers all over ebay, its dumb to not get them.

My best advice would be to copy the ebay headers to some degree... Trying to make a overly custom setup might be a bit hard.

[This message has been edited by darkhorizon (edited 12-05-2008).]

For a 3800SC 1.75" primaries would be better, if you have a N/A, then 1 5/8 is fine.

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11.425 @115.60
Best 60' 1.543 seconds
3800 S/C 4T65E

quote Originally posted by LFiero67: For a 3800SC 1.75" primaries would be better, if you have a N/A, then 1 5/8 is fine.

Ehh, togs/slp's used the 1 5/8's, and they have shown more whp than the extreme's in most simple builds, without greatly sacrificing torque/hp curves on the low end.

[This message has been edited by darkhorizon (edited 12-05-2008).]

I bought a set of custom equal lengths for my 3800 swap, I would say plan for access to the spark plugs, I literally can't changed spark plug number 3 without removing the header, and to remove the header I need to remove the engine, also plan out the spark plug wires, I melted 3 different wires in the first week. I don't know how much you like the sound of the 3800, but I have the pipes running 3" to a flowmaster 80, and it was just to raspy at anything over 2000 rpms, I added in a 10" resonator, and it calmed it down alot and smoothed the sound.

I would suggest going the stock rounting for the added length of pipe, and atleast 1 resonator to go with a regular muffler to calm the sound. That is just me though, I drive mine on the high way in the morning to work and it just wasn't too fun...


Chris

I made my own.

I can change my plugs in 20 minutes, oh yeah, and no plug wires melted yet either...

Put the plugs and wires on BEFORE you start mocking up the primaries.

http://i13.photobucket.com/...bo/IMG_1328Small.jpg
http://i13.photobucket.com/...bo/IMG_1327Small.jpg
http://i13.photobucket.com/...bo/IMG_1337Small.jpg
http://i13.photobucket.com/...bo/IMG_1340Large.jpg


http://i13.photobucket.com/...bo/IMG_1369Small.jpg
http://i13.photobucket.com/...bo/IMG_1373Small.jpg
http://i13.photobucket.com/...bo/IMG_1378Small.jpg


http://i13.photobucket.com/...o/P1060770Medium.jpg

1 5/8" primaries, 2.5" crossover, 3.5" downpipe, but I'm turbo obviously.

http://i13.photobucket.com/...bo/IMG_1595Small.jpg

Thanks for the pics and the tip on the plugs. I'm just worried about building these and then them running into something during the install, I'm sure theres something I'm not thinking of. I'll just keep them tight and hope for the best. Darkhorizon, I know I could have just bought something and bolted it on but thats not the way I am. I would just as soon spend 100 hours building a set of my own headers than spending 20 bucks on something that everyone else has, becase when I'm done with these they will be MY headers. No offense, to each his own.

20!!!! try $700-$1000 for stainless... That's why I'm doing my own too.

Haha yea I know they are more than that I was just saying if I could get a set for 20 I would still rather build my own just for the fun of it.

Well I got one bank of headers mocked up today and tacked, hopefully my pictures load

https://images.fiero.nl/pffimages3

did you check for proper bulkhead clearance?

This is just the rear side and as far as I can make out it its gonna be close but I'm not worried if I have to make a minor trunk adjustment. The front side will be routed significantly different because of the firewall.

Spark plug wire looks pretty close on the #4 cyl. You can still get a throttle body on that thing? I assume you checked all that though.

They look great!

[This message has been edited by Jncomutt (edited 12-08-2008).]

I agree looks like a hot TB to me......not so good

Am I the only one lost as to what way this is going? I am imagining that its going to collect around where the slave cylinder is, then run under the car? Sounds like ground clearance issues to me.

The throttle body isn't an issue with the I.C. raising it up plus there will be an additional heat shield between it and the header not to mention these will be ceramic coated. The pics are misleading as far as the plugs go, there is plenty of room for wires. The slave is a non-issue also, this car will have an F40 with the internal slave. Thanks for the advice though.

quote The slave is a non-issue also, this car will have an F40 with the internal slave. Thanks for the advice though.

I wasnt really thinking they were going to hit, more so just trying to figure out your overall header plan. Looks interesting.

Well I wanted to run the stock routing rather than dump straight down out of the back. Most all other headers running the stock route have very short primaries and are a terrible match for length. So far so well with this design. This bank's collector should end at about block centerline then run down towards the firewall behind the driver's seat and meet the other part of the y-pipe there.

I really like header threads, and the people who choose to make their own... keep it up!

I suggest mocking up the trunk wall and firewall sections so as you build, you can check clearances. Something like this (but ignore the SBC):

Nice mock-up. I have been planning to do the same and am waiting for a friend of mine thats about 15 minutes from me to test fit his 3800 again so I can go take some measurements and notes. I got my collectors today and was a little disappointed in them and man DONT EVER BUY ANYTHING FROM STAN'S HEADERS! They were like 72 some odd dollars and really aren't that impressive. Not to mention 25$ to ship a box that weighed maybe a pound and was the size of one of my valve covers. I see they keenly have stamped on the reciept in bright red letters "all returns subject to a 25% restocking fee". I should ship a turd back in the box and let them restock that... Had I known this i would have made my own merge collectors, oh well they're mine now.

Revision B

I got the protrusion down to under 5.5"
If someone would do me a favor with a 3800 and measure the distance from the exhaust port face to the rear bulkhead it would be much appreciated. I believe these will fit but I dont want to weld them up until I'm sure, thanks.

quote Originally posted by MJ: If someone would do me a favor with a 3800 and measure the distance from the exhaust port face to the rear bulkhead it would be much appreciated. I believe these will fit but I dont want to weld them up until I'm sure, thanks.

From the top of the head on the exhaust face keeping level to the trunk face I'm getting around 5.5"
About 5" from the bottom lip of the valve cover.

(Oh, I've also removed any heat shields and removed all the hangers)

[This message has been edited by Bubbajuju (edited 01-01-2009).]

The bulkhead sorta tapers off a bit twards the top, but at the widest point I have a little under 6 inches from the top of the exhaust port on the head to the bulkhead.

If the headers went above the mid valvecover area, it would run into a wall, where there is about 3-4 inches of clearance to the mid of the valvecover.

Edit,

Those headers most likely wouldnt even pretend to fit into my car, but I have my setup mounted very low, which forces the motor tward the front and right of the bay.

[This message has been edited by darkhorizon (edited 01-01-2009).]

Thanks for the info guys, I really appreciate it. I know this is going to be a tight squeeze but if I have to make a slight "trunk mod" it wont bother me.

ahh trunkside, I was measuring the front area, you should be fine clearing the trunk without issue.

any more pics? At first i didn't think it would fit. Im interested in what this setup will sound like.

Being 100% serious here, before I complete these would there be any interest in anyone wanting a set? If so, before they're complete I'll send the individual primaries out to get reverse engineered by probably Stahl and have them bend me up a few sets. I'll make jigs before I put them in the car so I can dupliate them. I also have the ability to ceramic coat them. I wouldn't intend on selling them though until I know for sure they fit the car without any interference. Let me know.